Black monoazo dyestuffs and process of making same.



UNITED STATES PATENT OFFICE.

FRANZ SCHOLL, OF HfiGHST-ON-THE-MAIN, GERMANY, ASSIGNOR TO FARBWERKEVORM.

MEISTER LUCIUS & BRfi'NING, OF l-IficHST-oN-THE-MAIN, GERMANY, ACORPORA- TION OF GERMANY.

BLACK MONOAZO DYES'IUFFS AND PROCESS OF MAKING SAME.

No Drawing.

Specification of Letters'Patent.

Application filed November 9, 1911. Serial No. 659,400.

Patented July 16, 1912.

To all whom it may concern:

Be it known that I, FRANZ SoHoLL, Ph. D., chemist, a citizen of theEmpire of Germany, residing at Hochst-on-the-Main, Germany, haveinvented certain new and useful Improvements in Black Monoazo Dyestuffsand Processes of Making Same, of which the following is a specification.

I have found that black basic dyestufl's are obtained by combining thediazo compounds of asymmetrical dialkylsafranins with 1-aryl-3-methyl-5-pyrazolone. The dyestuffs thus produced correspond tothe formula:

kilos of sodium nitrite. To this diazo solution which is of a pure bluecolor, is added a solution of 18 kilos of pyrazolone in about,

100 liters of water and 20 kilos of hydrochloric acid of 19 B. Theexcess of this acid is removed by adding some sodium acetate. After somehours, the mass is heated to 40-50 C. and salted out with a smallquantity of common salt. The dyestuff thus obtained has the formula: I

It is a black powder, soluble in water with a greenish-blue color,separating on addition of ammonia a blue precipitate, soluble inalcoholwith a violet color, insoluble in ether benzene and ligroin., Itdyes in a neutral bath unmordanted and tanned cotton and wherein Itstands for an alkyl group, X for a hydrogen atom capable of beingreplaced by a methyl group, and Y for an aryl residue; being blackpowders, soluble in water and alcohol, insoluble in ether, benzene andligroin, dyeing in a neutral bath unmordanted and tanned cotton andalso'artificial silk black tints.

2. As a new product, the dyestuif of theformula I A tral bathunmordanted and tanned cotton ()0 and artificial silk black tints.

3. The process of making black basic monoazo dyestufls, which consistsin combining the diazo compounds of asymmetrical dialkylsafranins with1-aryl-3-methyl-5-pyrazolone.

In testimony whereof, I aflix my signature in presence of two witnesses.

, FRANZ SCHOLL.

'Witnesses:

JEAN GRIIND, CARL Grimm).

